CALGARY, ALBERTA – “It was a run-and-gun game,” Matt Beleskey said after former Boston College star and 2014 Hobey Baker winner Johnny Gaudreau completed his hat trick at 3:30 of OT in a thrilling come-from-behind 5-4 win Friday night over Boston.

The Flames tied the game with exactly 1.2 seconds left in regulation after Brad Marchand scored on a penalty shot at 18:54 to put the Bruins up, 4-3.

“It was a bit of a wild one,” Marchand said after. “Definitely an entertaining one to watch but a disappointing loss.”

Former Bruin Dougie Hamilton was the culprit on the penalty shot, slashing the stick out of Marchand’s hands on a clean break-in. But Hamilton atoned in the overtime.

“Dougie deserves a lot of credit on the winning goal,” Flames’ coach Bob Hartley said postgame. “He could have shot the puck or pass through to Brodie that was carrying the rush. He showed lots of poise and lots of patience; just slid it to Johnny who was basically by himself. Very smart.”

The Bruins took their six-game unbeaten streak into the Scotiabank Saddledome after picking up one point Wednesday night in Edmonton, coming from behind for the third consecutive game to tie the game on a late goal by Zdeno Chara before bowing in a shootout.

One of the NHL’s most improved teams last season, the Flames were looking to regain that momentum after a bumpy road the past two months. They took down Dallas on home ice Tuesday night in OT after Hamilton potted the tying goal with two minutes to go.

Calgary — and that young talent — picked up right where they left off Tuesday on Hamilton’s first shift when Gaudreau put a backhander past Jonas Gustavsson 33 seconds into the game. It was Gaudreau’s seventh goal and 23rd point, both best on the Flames.

A perennial Norris Trophy candidate for the NHL’s best defenseman, captain Mark Giordano put the Flames up by two at 15:55 for the 2-0 lead; Gaudreau assisting.

Gustavsson, in net after his standout win against the Red Wings last week, was 5-1-0 with a 2.15 GAA.

Beleskey finally ignited a red light for the first time since Halloween for his third goal of the season to cut the Flames lead in half.

The second period began wildly with three goals in the span of a minute. Marchand ripped a 20-footer top shelf past Karri Ramo at 1:46 to tie the game with Brett Connolly and Zach Trotman assisting. Gaudreau was back at it 10 seconds later with his second of the game, prompting Claude Julien to pull Gustavsson for Tuukka Rask. Chara then again tied the game at 2:22; assists to Beleskey and Loui Eriksson.

Karri Ramo made the Flames’ save of the season at 6:44 robbing Connolly on a bullet off a cross-crease pass from Marchand. That would be the end of the scoring until the last minute of the game — and overtime.

Here’s what we learned from the 5-4 final as the Bruins move on to Vancouver for the final game of the western swing Saturday night.

Not something they want to do.

For the last six games, the Bruins have had to play either from behind or in tight games.

“Not something we want to do,” Chara said after.

“We fare better when we stay away from run and gun,” Claude Julien commented. “We kill ourselves with our own mistakes. Simple as that.”

“It’s fun to watch,” echoed Rask. “But it’s happened a couple times this year. A lot of times when we play that way we’re not going to win.”

Bruins picking up points of late, but big holes still linger.

“We have to be better off the start,” Marchand assessed. “Not let them get those two quick goals.”

“We created some chances and we gave them some chances,” Rask said. “But I didn’t think we played that good. We had the win but that last-second goal shouldn’t never have happened.”

“We had a chance to win it but couldn’t seal the deal at the end,” an exasperated Julien said.

Gustavsson comes back to earth.

After going 5-1 and stealing the game last week in Detroit in his best game in a Bruins’ uniform, Gustavsson played his worst hockey of the season Friday night, giving up three goals in a little over one period. Julien yanked him at 1:56 of the second period.

“Wanted to change the momentum,” the ninth-year Bruins bench boss said about the decision. It came within two seconds of working out as Rask held serve for almost the rest of the game.

The captains lead the way.

Chara played 24:44 and had two points on four shots; Patrice Bergeron played 21:08 with six shots and a plus-1.

‘Johnny Hockey’ making a huge impression in Western Canada.

Gaudreau ended the game with three goals and one assist for four points; and a plus-four. His 26 points lead the Flames’ roster. His three goals were distinctly different; his style and play was electric. He’s the real deal in Calgary after his sensational rookie year.